{"id":"CVE-2020-6817","aliases":["GHSA-vqhp-cxgc-6wmm","PYSEC-2020-340","SNYK-PYTHON-BLEACH-561754"],"url":"https://o3.security/vulnerability/CVE-2020-6817","summary":"regular expression denial-of-service (ReDoS) in Bleach","details":"bleach.clean behavior parsing style attributes could result in a regular expression denial of service (ReDoS). Calls to bleach.clean with an allowed tag with an allowed style attribute are vulnerable to ReDoS. For example, bleach.clean(..., attributes={'a': ['style']}).","published":"2023-02-16T22:15:10.650Z","modified":"2026-07-22T09:44:36.769250611Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":{"score":0.00713,"percentile":0.50543,"asOf":"2026-08-23"},"cisaKev":null,"exploitsKnown":1,"affectedPackages":[{"ecosystem":"PyPI","name":"bleach","fixedVersion":"3.1.4"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/mozilla/bleach/security/advisories/GHSA-vqhp-cxgc-6wmm"},{"type":"REPORT","url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1623633"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-22T09:44:36.769250611Z"}}